Gas Is a Better Option Than Coal on Our Path to Draw Down Emissions
By Paul Bledsoe
As the climate crisis worsens, the debate over emissions from natural gas is heating up, too. Unfortunately, both gas opponents and gas supporters have been cherry-picking the data, especially regarding the lifecycle emissions of gas, which under almost all circumstances are still lower than coal.
These contretemps are obscuring significant agreement between many gas suppliers, government regulators and climate campaigners about the need to dramatically reduce fugitive emissions of methane from the U.S. and global systems so gas can be as low-emitting as possible.
Switching from coal to natural gas in the U.S. has been responsible for three-fifths of U.S. carbon dioxide emissions reductions from 2005 to 2020. Across the U.S., major electric utilities continue to reduce coal. Duke Energy, for example, which operates in six states, including North Carolina, has retired more than 50 coal power plants and 7,000 megawatts of coal production since 2010.
One reason that the U.S. and other developed nations have used gas to displace coal is that gas power plants are compatible on the grid with renewable wind and solar, since new gas plants can come online within a few minutes when the wind stops blowing and the sun stops shining. This stands in contrast to other forms of baseload power, like coal and nuclear energy, which take much longer to cycle onto the grid. But coal, which has 50% higher carbon dioxide emissions than gas, still provides more than 20% of U.S. electricity and 36% of electricity globally.
Nonetheless, the U.S. and global gas producers must cut fugitive emissions of methane leaks far more deeply than they currently do. The good news is this can be done at a low-net cost for most emissions by retrofitting equipment and pipes while recovering more usable gas to reduce costs. Overall, requiring deep methane emissions reductions from gas in this manner is the far more likely road to cutting methane and limiting near-term global temperature increases — not the false dream of eliminating gas altogether, even as higher-emitting coal continues to dominate globally.
A study recently published in Environmental Research Letters (ERL) by a group of Harvard researchers illustrates both the opportunity, but also the problems with faulty assumptions. Importantly, the study focuses on the lifecycle emissions of natural gas primarily over the next 20 years, a crucial timeframe for climate protection.
And the ERL study correctly notes that the “net climate impact from coal is also influenced by [sulfur dioxide] SO2 emissions, which react to form sulfate aerosols that mask warming.” This genuine “masking” phenomenon means that reductions in coal use will not bring down near-term temperatures as quickly as reductions in methane and other short-lived climate pollutants. However, coal adds such massive amounts of the greenhouse gas carbon dioxide (CO2) that medium-term warming is hugely increased, meaning reductions in the emissions from the 2040s on must be that much greater.
Most troublingly, the study appears to make faulty assumptions about methane emissions from both natural gas and coal that puts a thumb on the scales toward the study’s stated finding that lifecycle emissions from these two very different energy sources are, in special cases, essentially equivalent.
For example, the ERL report begins by “assuming 1.5% sulfur coal that is scrubbed at a 90% efficiency with no coal mine methane when considering climate effects over a 20-year timeframe.” These are not at all typical conditions for coal production, especially globally in places like China, which accounts for more than half of global coal use. In fact, International Energy Agency data show that methane emissions from coal mines in China alone account for more than 25% of all global methane emissions from fossil fuels. And, worldwide, coal mines emit more methane than all oil and gas combined.
The study also seemingly cherry-picks “scenarios that combine varying methane leakage rates from coal and gas with low to high SO2 emissions based on coal sulfur content, flue gas scrubber efficiency, and sulfate aerosol global warming potentials” enabling the researchers to conclude, under very particular circumstances, an “estimate that a gas system leakage rate as low as 0.2% is on par with coal.” Seeking this conclusion appears to be the reason for the study’s tortured set of assumptions that do not apply to most coal power in practice. These flaws have been compounded by major news outlets’ coverage that focused almost exclusively on this false equivalency of coal and gas emissions without delving deeply into assumptions that make its findings untrue for most coal and gas.
However, later in the ERL study, the more widely applicable finding finally appears: “Global gas systems that leak over 4.7% of their methane (20-year timeframe) or 7.6% (100-year timeframe) are on par with life-cycle coal emissions from methane-leaking coal mines.”This key finding accurately represents emissions from coal rather than the rare conditions assumed elsewhere in the study. And it is more in keeping with the mainstream literature on the topic since, for example, the U.S. Environmental Protection Agency estimates life-cycle fugitive emissions of methane from natural gas of about 1.4%, meaning U.S. gas has life-cycle emissions far lower than most coal.
Meanwhile, some actors in the gas industry are also gaming the numbers, undermining efforts to reduce methane from gas production. Many conservative politicians construct false data to oppose measures to help the industry reduce methane, despite significant industry support for methane reductions. Although many in the industry supported specific provisions in the Inflation Reduction Act, including $1.5 billion in funding to help companies cut methane, some smaller producers still oppose such programs and seem to have an outsized influence on GOP policies.
There is no question that the U.S. and global gas industry must dramatically reduce methane emissions toward near zero, and over time use carbon capture to reduce CO2 emissions from gas, as well. Most responsible U.S. and global gas producers now accept this. But flawed studies and claims on all sides are muddying the issue, leaving lawmakers and citizens alike uncertain about the value of gas that will be needed to reduce coal and limit overall emissions for years to come. It’s time to deeply cut emissions of methane so that gas, along with related renewable power and other cleaner sources, can play its role in reducing U.S. and global greenhouse gas emissions toward net-zero by 2050.
Paul Bledsoe is strategic adviser at the Progressive Policy Institute and a professorial lecturer at American University’s Center for Environmental Policy. He worked as a staff member in the U.S. House, Senate, Interior Department, and the White House Climate Change Task Force under President Clinton.
This story originally ran in The Messenger on August 12, 2023.
